| 摘要 |
PURPOSE:To improve accuracy in detecting defects yielded on the surface of photographic papers, by detecting diffused reflected light from the defective parts on the surface of the photographic paper, and finding the defects by the various change in the diffused reflected light. CONSTITUTION:Light from a light source 10 is reduced by an ND filter 11 and polarized by a rotary scanner 12. The surface of color photographic paper A is scanned by the light through an Ftheta lens 13. As shown in the Figure, in the normal reflected-light region (a), the changes in amounts of light for silk A1 and glossy A2 of the color photographic paper are both large. In the diffused reflected-light region (b), however, the change in amount of light is small. A light receiving part for diffused reflected light 17 is arranged at a position, where the diffused light is detected, as a light receiving part. In this part, a plurality of photomultipliers and preamplifiers, which are operated by a high voltage power source 18, are enclosed. The outputs of the preamplifiers are made to pass an adding amplifier 19 and an HPF20, and a detected signal 21 is outputted. By receiving the light by the diffused reflected-light region in this way, the accuracy of a detect signal 22 is improved, and the detection of the defect is performed accurately. |
